Figures delayed until Tuesday as official says military must grow in order "to defend security and peace" in the world.

China has defended its booming military spending saying vast investments in the armed forces have contributed to global peace and stability, despite concerns among the US and Beijing's Asian neighbours over sharpening territorial disputes.

However, in a break with previous years, no figure for this year's defence budget was presented on the eve of the annual legislative session which will see new leaders placed into top government positions after they were elevated at November's Communist Party congress.

Speaking at a news conference on Monday, Fu Ying, a spokeswoman for the National People's Congress, said the figure would appear in the overall budget to be released Tuesday.

On the same day, party leader Xi Jinping will take over from Hu Jintao as president, as well as head of the government's Central Military Commission, as part of China's once-a-decade power transition.

In addition, the session approves top cabinet appointments such as the defence minister.

China's defence spending has grown substantially each year for more than two decades, last year rising 11.2 percent to $106.4bn, an increase of about $10.7bn. Only the US spends more on defence.

Pirate patrols

Fu said China maintained a strictly defensive military posture and cited UN peacekeeping missions and anti-piracy patrols in the Gulf of Aden as examples of Beijing's contribution to world peace and stability.

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"As such a big country, China's inability to ensure its own security would not be good news for the world," Fu said.

"Our strengthening of our defence is to defend ourselves, to defend security and peace, and not to threaten other countries."

Kerry Brown, executive director of the China Studies Centre at the University of Sydney, told Al Jazeera that although China has become a little more "canny" about how it releases statistics, they would probably release the military budget soon.

"You can't really conceal something like this," he said.

Brown pointed out that despite the large amount of funds going to military spending, China spent $111bn on internal security last year.

"That told us something about the fact that China, in order to keep itself stable, spends more money, at least on the books, in order to keep its borders and its environment stable."

Continuing disputes

This year's legislative session comes amid a continuing standoff with Japan over disputed islands in the East China Sea.

Ships and planes from both sides have repeatedly confronted each other in the area, and another Chinese spokesman warned on Saturday that Japan would bear full responsibility for any "unintended clashes".

China's feuds with Vietnam and the Philippines over territory in the South China Sea have also flared periodically in recent months, while Beijing has been unnerved by the US military's renewed focus on the Asia-Pacific, including plans to station marines in northern Australia on training missions.

Outside concerns about China's military build-up are also fed by doubts over the reliability of the defence budget figure, which is widely believed to exclude foreign military purchases and other items.

In its 2012 report on China's military, the US defence department estimated actual spending of $120-$180bn in 2011, well above China's official figure that year of $91.5bn.